Big Fucking Shooter
by burakkurokkushtBFG
Summary: Even with Black Rock Shooter finally at their side, the last remnants of humanity still struggle to survive. What they didn't know was that another titan slept in the depths of the earth, something much more powerful, even more powerful than Black Rock Shooter. Also Rock's past and how she got her powers are finally revealed...
1. Chapter 1

**Disclaimer: I don't own Doom or Black Rock Shooter.**

 **Prologue:**

 **Humanity**

The future was far darker than we expected. Humanity is at war with an alien race for nineteen years. We've lost it bad. All governments and armies were wiped out of the face of the Earth and only a few humans have survived the slaughter, now Earth is a deserted wasteland, almost devoid of life, a shell of it's former glory. But we found our hope for the future after years fear: Subject Black Rock Shooter. Our finest soldier, our pillar of hope, humanity's final warrior, have finally awakened from her slumber. But even with her assistance, it isn't enough. The aliens still have the upper hand, and now they're closing on their objective of exterminating the last few of us. We've buried our hopes on the most profound darkness. But then a miracle, if you want to call that, happened. The mightiest warrior had woken up and shed light on Rock's past: Project ADAM. And he brought us out of the darkness.

 **Chapter 1**

 **Rude Awakening**

 _ **BGM: Aliens, Say Your Prayers!, By Bobby Prince.**_

Not too faraway from San Francisco, USA.

Military Underground Base, Codename: Genesis

Research Division Of Subject 2018-0, Stasis Section, Subject Containment Chamber.

 _ **Rebooting systems... All systems nominal. Base Lockdown ended. Initializing Chamber shutdown...**_

After the base warning and a load of steam and metallic sounds, the chamber opened and a man falled into the floor. A after sucession of moaning and sighing, he quickly stand up and looked around. It doesn't look like anything the UAC have built, since it looked much older and outdated, plus it looked like abandoned. No one enters this base for at least some years. But then something catches his attention from the other side of the room.

It was his armor. Quickly suiting up, after checking if everything was in the right place, he noted something: it appeared someone was desperately trying to do something with the armor, since there was a lot of tools (most of them broken after somekind of struggle, probaly trying to do something with the suit). Poor bastards. A note was in the floor, near the stand where the armor was displayed, that reads:

"We tried everything, General. The armor is impervious to any kind of damage and all of our tools, even the most advanced ones, they break like matchsticks. Damn, we tried even diamond drills and lasers! It appears the armor and the man are like two components of the same machine, one will not work without the other. I suggest we move on with the ADAM Progam or all hope will be..."

The rest is illegible and have faded away. ADAM? What's the meaning this? This isn't looking good. The Marine opened the sealed heavy door with ease and then heard afamiliar computer voice,coming from somekind of mini-drone:

"It's about time Marine. Do you remember me, VEGA?"

He nodded.

"Good Marine. I've been waiting for you to wake up from your slumber. Quick, follow me to the control room of the base."

Following the drone, while walking in the corridors of the base, he noticed that was almost like the Argent Energy Plant, after the Hell Wave. A lot of bullet holes and water leakages everywhere, coupled together with various animals and some skeletons. Some unpleasant memories came back...

After a long walk (damn this base is really big), they arrive at the control room and then VEGA starts briefing Doomguy about what's happening, after uploading itself on the main computer of the base:

"Marine, apparently you arrived in this alternate Earth in the year of 2031. I don't know how you got here, but it's apparent that Dr. Hayden double crossed you in the end. Continuing, you landed in the Mojave Desert, unconscious and you were recovered by the US Military and brought here to this facility and somehow they, stripped you of your armor and guns (somehow), and put you some type of stasis chamber and started experimenting with you. They retrieved many blood and DNA samples from your body, in hopes of finding something useful to them."

"One year later, however, an Alien race started invading Earth and all humanity banded together to defeat them. But they were losing and being exterminated in a fast pace, so they turned their hopes to you. They've tried many times to wake you up, with no success. Then they've started a program called "ADAM" (your codename), and gathered volunteers. The rest of the data is corrupted, but what I've gathered that you're related to some subject called 'Black Rock Shooter'."

"Also, in their desperation, they've damaged the Tether System and we need to fix it, if we want to go back to our timeline. From the information I've managed to recover, the UAC/Alien technology are very similar (especially since they make use of gateway technology), so if we find their main base (and their main portal), we'll be able to reverse-engineer their tech and repair the Tether Prototype. Grab your guns in the Armory, upload me into your armor and let's get out of here."

After rebooting VEGA into the Praetor Suit and getting back his arsenal (untouched and with all mods, even the BFG-9000), VEGA guided him to the exit. After destroying the massive steel door (and some aliens that were trying to invade the base) with a barrage of rockets, he looked towards the wasteland. The once great city of San Francisco now was just a pile rubble and filled with murderous aliens. The Marine swapped the Rocket Launcher for the Chaingun, focusing on finding that alien base and that so called "Black Rock Shooter", he thought to himself:

"Time for the final judgement".

\- To Be Continued...


	2. Chapter 2

Disclaimer: I don't own Doom or Black Rock Shooter and stuff.

 **Chapter 2**

 **Hell Beneath**

 ** _BGM: Countdown To Death, by Bobby Prince._**

While moving towards the city, the Marine ended up in a highway, filled with long queues of vehicles in various states of decay. A lot of many military tanks and checkpoints and sadly, many skeletons and bodies of soldiers. Bastards. Instead of being victims of the machinations of the UAC, many innocent people died because some maniacal-killer aliens decided to make Earth their new playground. The Marine is determined to destroy every single one of those motherfuckers, and make sure they burn forever in the inmost dens of Hell.

While he was wandering in the road, he noticed something noticed in the distance. Imagine if a Pinkie and an Alien both got drunk at a party and they decided to have some fun afterwards. You've got the picture. He saw a large pack of those ugly fuckers, attacking some kind of small animal.

He didn't care about them at first, since he could slaughter them in a second with the Chaingun, until he saw what was their prey: an innocent girl. He started running, trying to closing in as fast as possible, while annihilating some abominations with the Chaingun. He killed every last one of them. In the end, only blood and gore were left behind. Then he went to check on how the girl was. Sadly, it was already too late. Her body was in a pretty bad shape. No doctor in this world could do anything to her. Maybe with the advanced medical tech at the UAC, she could be saved, but this wasn't that Earth...

"You rescued me... thank you...", while coughing a lot of blood.

Her whispering dragged him out of his thoughts.

The girl was in her teenage years and her blond her was almost devoid of color and dirty, with leaves and insects, indicating that she didn't a shower for weeks. Also, she had clear signals of starvation. Such a shame. No human being deserves to suffer like anything like that.

"You're a soldie-er righ-ght-t? You mu-st-t ha-have a-a-a gu-gun-n rig-right?"

The Marine made a confused expression under his helmet.

"Please do it-it, I've got nothing more he-re-re... the monsters... they've took everything from me... please..."

Her request caught him of guard. He only killed Former Humans and Soldiers, not normal humans. He didn't wanted to that, but in the end this was the least he could do for her, after he failed to save her from the new "Pinkies". The Marine pulled out his UAC-EMG Sidearm, putting it near her head. After a quick "PEW", the girl's body stopped moving. It was over. The Marine made a quick funeral to her and after final salute, he continued his journey to San Francisco. He would honor her memory and atone his failure by killing every last of those fuckers.

Two hours later:

 _ **BGM: Operation: Alien Overlord, from Quake 2.**_

After a long run, he was finally on the east part of the city. The landscape was much worse than the highway. A lot of destroyed buildings, rubble and vehicles (military and civilian alike). Just as expected, these poor bastards didn't stand a chance. He walked towards a military checkpoint, to gather some intel on the situation here on San Francisco. Luckily for him, there was a computer still kickin' on the main barracks. After snooping around in the military files, he found out that entities called "Apostles" led the invasion on this Earth, and even with their superior firepower and tech, the human forces were able to kill eight of the fifteen original ones. Now only seven of them remain.

Of course, the arrogant bastards underestimated the human race. They really thought that Earth would go down without a fight. It serves them well. The Marine now knows who he has to destroy, in order to be able return home. After getting out of the barracks, the Marine wandered around in the ghost city. It was too silent, and that was a problem. Never underestimate your opponent, never let your guard down. Maybe he'll find survivors holed up somewhere.

"Marine, I'm detecting multiple lifeforms near your position, maybe hostiles. Prepare to engage."

After following the waypoint set on the minimap, he found himself near a swarm of aliens troopers and many other types, setting a camp in a former park. Hundreds and hundreds of aliens carrying out their extermination campaign. This is going to be a mess…..

He started by deploying the Chaingun as the Mobile Turret, ripping apart many unsuspecting aliens. The commanders tried to organize the troops, but they were also ripped in half by the storm of 15mm slugs, spilling blood and guts everywhere. But the other ones started retaliating the aggression, firing everywhere, killing even their own comrades. The Marine quickly swapped the Chaingun for Super Shotgun for close combat. He advanced and started blasting many of the troopers, merciless. Performing many glory-kills, smashing heads and crushing bones alike. After 10 minutes of battle, the camp was clear of hostiles, Doomguy was just finishing off some melee hostiles with his Chainsaw. The field was filled with a mountain of dead, mutilated aliens, coupled together with river of blood and guts.

While he was finishing off the resistance, a purple figure was watching at the distance, in the roof of ruined skyscraper.

"He's good at what he does... I'm going to keep an eye on this _cabrón_ for now on. I can't wait to fight him...", the purple dressed girl said, with a lustful smile, while disappearing into the darkness...

Finally, the Marine killed the last bastard and looked down. He was literally "Knee Deep In The Dead". Who's next?

What he didn't expected was a giant alien come after him. It was big, but nothing like the Titan back at the Hell. A skyscraper of alien, it appeared to be more robotic in nature, with a monumental scythe ready to slash anyone apart. Doomguy simply changed the Super Shotgun for the Gauss Cannon (Siege Mode). Time for round two.

But of course his killing spree didn't go unnoticed...

\- To Be Continued...


	3. Chapter 3

Disclaimer: I don't own Doom or Black Rock Shooter .

PS: If anyone of you guys have talent, please make some BRS/Doom fanart and link it on the review tab. It would be very appreciated.

 **Chapter 3**

 **Enter: Black Rock Shooter**

 ** _BGM: Quad Machine, Quake 2._**

 ** _Not too far from where Doomguy was battling the Dead Master:_**

"So, Rothcol, do you know what we're exactly going to retrieve? Because I didn't understand why Marion is so freaked out about this 'Project ADAM' and that 'Genesis Facility'? God, all I wanted is get some cold beer and enjoy myself a bit, until we became an extinct especies. Plus, I hate working with that thing", while pointing at Rock with his rifle.

"For the last time PHOBOS, knock it off! You don't have to like her. You just have to follow orders, shoot aliens until they die and shut your damn mouth! If Marion said that 'Project ADAM' must not fall into the aliens hand's or 'all of last ray of hope will be lost forever', then it's a serious matter for the UEF. Since I know you don't have a better solution, I suggest to you to shut up and focus on the mission."

Rock simply ignored him. But after hearing about that 'ADAM', actually something rang a bell on her memory. But she didn't know why. Must be some side-effect of being a living weapon. She felt really lonely since the awakening, but every time she looked at her "Rock Cannon", these feelings would always go away.

"Okay, sir. I understand. We're going to check it out right now. Then we'll proceed with the mission. I know it's the utmost importance to retrieve ADAM. Yes, sir."

She was brought out of her thoughts by Rothcol, giving a new briefing:

"Allright ladies, change of plans. HQ got reports of a massive battle going on the old park. The only info we got is that a humanoid being is dueling with a Dead Master right now, after wiping out an entire camp of aliens. Let's move!"

"Oh, you didn't said anything like that last night, my sweet little Rothcol...", PHOBOS teased.

"Go fuck yourself PHOBOS".

Rock was surprised. She thought she was the only super weapon of humanity. She didn't like the meaning of this. Or maybe this new "player" will actually help them. If anything, the Rock-Cannon is always ready to solve any problem. Actually, she was looking foward to meet this new ally/enemy.

The trio then started moving towards the new mission objective.

 _ **BGM: The Leaning Tower Of Babel, The Darkside Of Phobos by The Evil Horde.**_

The battle was intense. Doomguy dodged every strike from the giant scythe flawlessly. This giant sucker only rely on pure brute, blunt force. No tactics, no strategy, just force. What a joke. But Doomguy was really tired of playing with this thing. Shot after shot, it was clearly taking damage, but it continued to attack relentlessy.

He needed some more firepower to end this fight now. And then he saw what he was looking for. A Quad-Damage Power Up. Of course ,the exhaustion of Argent Energy from the Praetor Suit build up and formed a Power Up. Exactly what he needed. He moved towards a crumbled building and shot the beast in the head to infuriate the beast and make it fall in Doomguy's trap.

And it happened exactly as he predicted: The giant beast tried to slash him in half, and as Doomguy dodged to the left and then, the giant scythe got stuck on the crumbled build (and on terrain), and as the Dead Master tried to remove the weapons, Doomguy grabbed the purple sphere, looked the skull symbol on it, and slammed the sphere on his chest. He felt the power flowing on his suit, going to his gun.

Then he engaged the Siege Mode on the Gauss Cannon, the Argonian gas building up time four times greater than the normal use. Then he waited for the right moment and when the giant alien finally retrieved his gun and turned around, the Marine fired. The bolt, railgun-like shot, ripped apart the arm (and a great portion of the chest) of the beast, and it falled into the ground, letting a cry of pain for it's losses, but still alive, barely. He swapped the Gauss Cannon for the BFG-9000, intending on giving the annoying beast the same special "treatment" he gave to the Spider Mastermind.

Meanwhile, the trio got the location of the battle...

"Rothcol, have you heard that cry?! That was absolutely a Dead Master.",

"Yes, I've heard that. It appears we got late to the party boys."

Rock didn't say nothing. He was already impressed by this enemy/ally abilities, since he/her defeated a Dead Master alone. Actually she was dead curious to see what the humanoid being looked like.

But then the trio saw one of the most unbelievable sights they've ever seen: literally a mountain of dead aliens of all types, and a lake of blood and guts. They couldn't admire it more because something else caught their attention:

At the distance , they saw an agonizing Dead Master, almost like it was begging for life. In front of it, a humanoid being in a green, full body battle armor was holding one of the biggest guns they've ever seen (it looked like a giant cannon to be honest). I was metallic in nature (with red details), with a green, glowing cylinder that was spinning really fast, with the letters "BFG" written on the other end of the gun.

Both the being and the gun were surrounded by a purple aura. The three decided to wait and watch.

 _ **Back at Doomguy...**_.

The Marine walked up towards the dying giant, and using his boot, opened it's mouth, while keeping his left arm on the upper jaw to keep it open. He shoved the BFG-9000 in the beast's mouth and pulled the trigger. After a brief "WHIIIRP" and the 0.5 sec charge, a green-purple, giant ball evaporated the Dead Master's body, leaving nothing but a green, purplish giant pool of goo where was the giant alien. One ticket back to Hell you ugly fuck.

Then he noticed something shinning on the pool of goo. A green sphere. It looked liked a Argent Energy Cell, but it was greenish instead.

"Well, apparently that thing left a reward for you, Marine. Go get it.", VEGA advised.

The Marine walked towards the strange object and grabbed it. Instinctively, he crushed it with his hand and after a electric green electric discharge on the suit, nothing apparent happened.

But then VEGA announced:

"Marine, after running some diagnostics on the suit after the electrical discharge, you now have the ability to absorb alien energy in order to upgrade your weaponry. Sadly, you have to absorb a lot of energy for you to be able to do it. But it was enough to upgrade your pistol. Check it out."

The Marine quickly pulled out his former EMG Pistol. Now it was painted black and red, with a red pulse on the back of it. He proceed to test it, shooting at ruined wall. A big hole appeared on what survived of the wall. Nice.

But then a strange, feminine voice started talking from somewhere:

"Yeah, definitely you're far stronger than I expected. You'll be a serious problem in the future, Doomslayer. But in the end, you'll be a very nice meal."

Nothing on the radar. Great, now we have a mind controling alien, nothing a shotgun blast to the face can't solve. And many have said that in the past and well, they're all splattered on a wall somewhere. Plus, these cowards always make use these tricks to hide somewhere, just like rats.

Then a interruption came from behind:

"You saw that shit Rothcol?! That's 'THE GUN'!"

"Yes, I saw that PHOBOS, but be careful he maybe a hostile."

"Don't you remember that old saying, Rothcol ?: 'The enemy of my enemy is my friend.'"

"Yeah, yeah but we still have a mission to complete, don't you remember. We must retrive it at all costs."

Looks like the survivors have found him. At least he didn't had to wander in the city anymore. But since he didn't know if they were hostile or not so he turned around quickly, and assumed a combat stance with the BFG.

It would be pretty standard survivor encounter if weren't for the third element of party: a girl (16 years old at best), dressed in black and with a huge gun attached to her arm, with a blue flame coming from her left eye. Something was really off about her.

Then she also assumed a combat stance, point the huge cannon to the strange soldier. He also retributed the gesture, pointing the BFG at her. Both combatants were determined to annihilate each other.

"Put your weapon down Rock. I think we found what we were looking for.", the so called Rothcol ordered her.

Rock and Phobos looked confused.

"Look at his right shoulder pad, people. Plus, he also have your symbol on the same spot."

The Marine looked at where the stranger was pointing. It was written "ADAM", and below the word, a star shaped (in white color) appeared. He must haven't noticed it during the past two days.

"Well sir, wecolme aboard.", Rothcol said, going near him and giving a pat on the back of the strange soldier.

\- To Be Continued...


	4. Chapter 4

**Chapter 4**

 **Into Sandy's City**

 _ **BGM:**_ _ **Into Sandy's City**_ _ **, By Bobby Prince.**_

"Ouch! This damn thing is hard, really _hard._ "

Rothcol said, while taking care of his supposed injured hand. Be glad that it is only a little pain on your hand, other incidents ended up in much more serious injuries. Well, at least they found you. Wandering in this pile of rubble in search of the Resistance would be a real pain in the ass and a waste of time. But that girl in black, something is really off about her. And her gun apparently has multiple firemodes. And plus you didn't liked her aggressive attitude, since you're here to help them after all.

But apparently that spoiled brat, thinking that he had hurt her friend, decided to make a rash move on her own:

" ** _Agressor Mode_** ", she angrily muttered.

She fired a barrage of bullets against the Marine, while Rothcol jumped to cover. The projectiles simply bounced against the armor, and seconds later, he was still there like nothing had happened. She was definitely shocked by what transpired now and didn't noticed the war machine coming at her, pulling a confused expression.

The Marine had enough. he decided would give her a "good lesson", not kill her but teach her a thing or two, but he was stopped by a hand.

"I apologise in advance, sir. She's very volatile as you can see, please forgive us for our imprudence. Please don't do anything harsh to her."

The Marine complied, sighing to the guy. But it's the first and last time someone would get away after attacking him, plus he would never hurt an innocent being, only subdue them if it's necessary. The guy smiled, but then he turned to the girl:

"Rock what's wrong with you?! He clearly didn't do anything wrong, nor did he hurt me! Don't you remember what I told you a few days back? You definitely need military training. You can't never make a rash decision on the battlefield. Be glad he isn't mad at you, otherwise this could end really bad for you."

"So, why our knight in shining armor wouldn't grace us with his face at least? If he's gonna work with us, I want to see that beautiful smile you have... ", PHOBOS said, approaching the Marine with the intent of taking off his helmet. An intent that was met with a shotgun pointed right at his face.

"Whoa, whoa. Sorry to bother you big man, I didn't wanted to annoy you, just point this damn thing somewhere else if you can. Jeez, this guy don't know how to take a joke."

The Marine lowered the shotgun after seeing his intimidation tactic worked, as usual. A shotgun blast to the face is the perfect cure for being an annoying cunt. What a pain.

"PHOBOS, can you please stop this nonsense, before someone gets hurt really badly? Sorry sir, sometimes I think that I'm working with rookies instead of real soldiers. So could you please accompany us to HQ?", Rothcol said.

The Marine nodded again.

"Okay people. Pack your things and let's go. We're are going back."

But the Marine couldn't shake the feeling that they were being following. By something evil and powerful. Since the damn thing refused to show itself, to make more easy to dispatch it to oblivion, he would wait for the unknown enemy to make it's first mistake.

 ** _Somewhere in the ruins of San Francisco..._**

During all the long walk to the one of the outposts of the Resistance, the small girl wouldn't leave his side, maintaining a distance, but always looking at him. Great, now we have creepy girl in skimpy clothing, armed with an overpowered cannon. He simply ignored her and hoped that she wouldn't try him again. Otherwise…

Finally, after a long walk, they finally got into the "outpost" (more like a pile of rubble of what was a military base), the guy named Rothcol found a radio, and after he handed a blanket to both PHOBOS (that name brings memories) and Rock (What an… interesting name for a girl), he found an old ham radio and started radioing in to their HQ. The Marine took the opportunity to get a look around the terrain, since the "presence" was still there, and assess the situation in case a battle ensues. But after looking around for quite a while, the sensors and the radar started to pick up alien energy. But it was right here on this base, on the courtyard, where the resistance guys were.

When he got back to the courtyard, he saw that Rock was gone and both soldiers were busy on the radio, probably reporting to their CO. The Marine simply switched to the Gauss Cannon and prepared for the worst. Following the radar, he found Rock and the assailant outside the base, casually having a conversation. The "alien" was very human in appearance and was wearing a purple, witch-like outfit, complete with a giant futuristic scythe.

"Marine,", VEGA interrupted,"I believe we're dealing with an Apostle here. Lethal force is advised."

While the Marine was calmly walking towards the two "chittchatters", the hostile felt the Marine's presence and quickly turned around to see him. Happy that her prey actually found her first, she quickly switched her attitude and took Rock as a hostage. The Marine assumed his combat stance, ready to blast the alien's head clean off with the Gauss Cannon.

"Me and my _**jefe**_ were waiting for you, **Doom Marine**! And now, you'll be ours!"

In the distance, an old radio started to play again:

"I don't want to set the world on fire..., I just want to start a flame on your heart..."

\- To Be Continued...

Note from the author: Updates will be in a irregular basis for now on.


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